Design, Fabrication, and Testing of Advanced Composite AH-1G Tail Section (Tail Boom/Vertical Fin).

The purpose of this program was to design and fabricate a primary structural component for a helicopter using advanced composite materials. The component selected was the tail boom and vertical fin of the AH-1G Cobra helicopter. The composite tail boom was required to meet the existing metal tail boom structural design and stiffness criteria, and to be interchangeable with the metal tail boom. Design objectives were to reduce the life cycle costs, to minimize the parts count, and to lower the overall weight of the existing structure. The composite tail boom successfully met the design criteria and objectives and completed all the structural and flight tests. The composite tail boom structure is a semimonocoque configuration using a sandwich wall construction. The inner and outer skins are fabricated of Thornel 300 graphite filaments with an epoxy resin, and the sandwich core is Nomex honeycomb. The wet-filament-winding technique was used in the fabrication of the major components. This research and development program established that primary helicopter components could be efficiently fabricated from composite materials. The resulting structure would have a higher fatigue strength and a lower life-cycle cost than the metal structure, and it would have an improved ballistic tolerance. Author